New Labour candidate Clare Curran won selection by beating three-term MP David Benson-Pope, who had consistently produced one of the country's largest majorities for his party.
Crucially, the party vote under his watch never went below 18,000 and in 2005 it topped 20,000.
National candidate Conway Powell is contesting his second election and managed in 2005 to reduce Mr Benson-Pope's personal majority by about 4000 votes.
If he can help National secure 47% of the party vote, and New Zealand First does not reach 5%, Dr Powell could enter Parliament off the list to give Dunedin five MPs: two Labour, one Green and two National.
Both candidates told the Otago Daily Times yesterday they had worked hard and were heartened by the support they had received from voters.
Ms Curran, who stopped full-time work in July to concentrate on campaigning, needs to show Labour head office its investment in supporting her over Mr Benson-Pope was worthwhile.
She needs to deliver the two ticks for Labour and get close to the majorities of her predecessor.
When Finance Minister Michael Cullen won the seat in 1996, his share of the total candidate vote was 36%.
Mr Benson-Pope increased that share in 1999 to 51%, rising to 62% in 2002 and falling to 56% after a strong campaign by Dr Powell in 2005.
Dr Powell said he had received much more financial support for this campaign, with people "coming out of the woodwork" with offers of cash.
"I had a good team last time and I have a good team this election, but a lot more people have volunteered to help. We will have scrutineers at 50% of the booths on Saturday, something we could not do last time."
He had knocked on about 5000 doors during the campaign, finding that people were keen for a change.
They did not like being told what to do by the Government. There did not seem to be an anti-Clare Curran feeling, just dissatisfaction with Labour.
Ms Curran had Dr Cullen campaigning with her in South Dunedin yesterday.
"A lot of my campaign is about building relationships with people and seeing as many community groups as I can. I have been getting in front of people and talking to groups. The invitations have been coming in - more all the time.
"A lot of that is not visible from the outside, but the campaign has been about understanding the issues."
Ms Curran said she had built up a strong campaign team who had been out delivering an "enormous number of brochures".
Both candidates will finish their campaigns out on the streets of Dunedin South today.
Dr Powell and his team are planning a "big walk" through key parts of the electorate and Ms Curran and her team will start the day waving placards at intersections before walking in King Edward St and Green Island.
This evening, she will be visiting pubs in the electorate, talking to working people as they finish for the day.
